The invention together with the attached drawing relates to a further development of manually operated grease guns for lubricating machines, especially agricultural machines and construction equipment.
Such a grease gun, which is also referred to as a manually operated grease gun, is known from the EP 0 666 449 B1. Grease guns of this construction are operated with one or two hands and require the expenditure of appreciable force, especially when a larger number of lubricating sites are to be supplied. This is especially the case for construction equipment and agricultural machines, for which maintenance must be carried out not in the workshop, but after each shift at the respective work site under unfavorable conditions.
It is an object of the invention to facilitate the lubricating process by means of a motor-driven grease gun, it being possible to provide the inventive device with a motor, which is permanently connected with the device, and an attachment, for example, an electrically driven drill, capable of rotating clockwise or counter-clockwise and battery-operated or mains-operated.
Battery-operated drills, when used pursuant to this invention and in combination with a conveying piston with a diameter of 10 mm, enable a larger number of lubricating sites to be supplied with a pressure of up to approximately 500 hPa with one charge of the battery.
Exchangeable batteries can be charged from the D.C. power supply system installed on the machine using a suitable transformer. Moreover, this invention can be combined easily with a lamp for illuminating the site to be lubricated.
The work of lubricating machines at sites, which often are difficult to access, is frequently physically taxing. With the invention described, this work can be clearly facilitated and accelerated, so that the availability of the machine is increased and the state of care improved. This is the case all the more so, since the device weighs less, is smaller and more easily handled and, especially when constructed as a combined device, can be produced very inexpensively and is more reliable in operation.
Pursuant to the invention, the pressure on the conveying piston is generated by a heavy-duty thread. This heavy-duty thread, preferably a saw tooth thread, is an internal thread, which is formed in a unit, which is named a driving sleeve pursuant to the invention, and with which the driving piston is firmly connected. Moreover, the heavy-duty thread is guided in a frame or housing and prevented from rotating by side stops.
In a further development of the inventive concept, a drive shaft runs, which is equipped with a complementary thread and, outside of the frame or housing, is constructed round or polygonally for taking up the drive motor. This drive shaft, which, aside from the frame/housing and the drive sleeve, represents the three main parts of the motor-driven grease gun, is to be provided with an annular stop for the thrust race, which lies on the opposite side of a stop, which is permanently mounted in the frame/housing. The construction of the thrust race must be such that, together with the stop of the housing, it can transmit the pressures, which arise, reliably and must, preferably be a thrust bearing.
The tensile forces, which arise during the suction cycle of the conveying piston, are also absorbed by a bearing constructed as a thrust bearing, which also acts on the stop of the housing/frame, however from the opposite side. This bearing is adjusted and fixed on the drive shaft in such a manner that, with the exception of the bearing clearance, the drive shaft is rotatable but not displaceable in the axial direction within the frame/housing.
In a further development of this inventive concept, the drive shaft, for structural or economic reasons, can be constructed with the drive sleeve and complementary to the conveying piston with the external thread.
Pursuant to a further development of the inventive concept, in the case of a drive, which is permanently connected with this grease gun, an electrical or mechanical reversal of the direction of rotation is provided at the ends of the path of the conveying piston; when a xe2x80x9cdrilling screw driverxe2x80x9d or drill, the direction of rotation of which can be reversed, is used, the reversal of the direction of rotation can be carried out manually.
Moreover, in pursuing the inventive concept, limiting the torque in order to avoid damaging the heavy-duty thread for the compression cycle as well as the suction cycle is regarded as advantageous.
In a further development of the inventive concept, the grease gun for a motor drive can be used for plastic or viscous compositions.